Field of the Invention
The invention relates to a magnetic particle and an organically surface-bonded metal or metal oxide material, and a method for preparing the same.
Description of the Related Art
Organic-inorganic composites can present novel high-performance properties, the key to producing which is resolving organic-inorganic interface linkage. Conventional approaches mostly rely on physical interface methods, such as various spraying or coating techniques. The physical coating is not stable, and easy to fall off. Some chemical coating methods are also used to resolve organic-inorganic interface problems, such as surfactant coating, silane coupling agent method and so on. Most of the interfaces are formed through weak chemical interaction, such as coordination bond, hydrogen bond, electrostatic interaction and van der Waals interaction, which raise serious questions concerning the long-term stability. Therefore, a strong and stable bonding at the organic-inorganic interface remains a challenge to science and technology.
Functionalized magnetic particles can be accurately positioned, moved, controlled and separated under the control of applied magnetic field due to their special magnetic effect. As a kind of magnetic carrier or magnetic marker, functionalized magnetic nanoparticles can carry various drugs, or couple various biological ligands, thus form a variety of biological magnetic assembly system. They find a wide range of application in biological research, medical diagnosis and treatment, drug screening, biochemical products separation, food and environmental microbiological testing, and many other areas. Meanwhile, functionalized magnetic particles, especially those having nano-size have large specific surface area. They also have potential application in the field of chemical catalysis, environmental wastewater treatment, heavy metal recycling and etc.
There are many methods to synthesize magnetic particles, these inorganic magnetic particles have no functional groups on the surface, and thus it limits their practical application. Resent approaches are forming magnetic particle-organic material composites, including forming core-shell structure with organic material, such as surfactant coating, silanization method and etc., and forming magnetic polymer particles with polymers, such as blending embedding method, interface deposition method, monomer polymerization method and etc. However, the above methods have shortcomings and deficiencies of one kind or another. New method remains to be explored in order to produce functionalized magnetic particles with controllable size, narrow particle size distribution, strong magnetism, and high content of surface functional groups, as well as simple synthesis process.